Injection pump



. June 1932- E. T. ADAMS 1,862,132

INJECTION PUMP Filed Oct. 20, 1928 2 Sheets-Sheet 1 a/ a I I I I7 /7 2/l8 2a I 26 ,e4

z1 35 *i- 24 z INVENTOR F|G.l EDW/IR, ZFID/Ws A TORNEY Patented June 7,1932 UNITED STATES PATENT OFFICE EDWARD 'r. ADAMS, or PHOENIX, ARIZONA,AS(S IG1\TOR 'ro FAIRBANKS, MORSE & 00., or CHICAGO, ILLINOIS, ACORPORATION or ILLINOIS INJECTION BUM? Application filed October 20,1928. Serial No. 313,864.

This invention relates to improvements in injection pumps, andparticularly to improved means for altering the displacement stroke ofinjection pumps for internal combustion engines. i

An object of this invention is the provision of an improved assembly inwhich the parts are few in number, and of simple, rugged construction.

A further object is the provision of means for regulating the length ofthe plunger stroke, and hence the quantity of oil delivered, through asimple linkage arrangement adapted for control by a governor or thelike, and whereby the amount of fuel delivered to the engine. iscontrolled by the effective length of the injection pump plunger stroke,rather than by the more usual regulation of the closing of the pumpsuction valves.

Further objects are to provide a construction, in which betterregulation of the fuel injection is maintained throughout the operatingrange of the engine; an improved construction in which the tendency forthe engine speed to fluctuate unduly, following I changes in load, isminimized.

Further objects and advantages will appear from the following detaileddescription of parts and the accompanying drawings, in which Fig. 1 is asectional elevation through the pump housing of an engine, to

which a preferred form of the invention is applied; Fig. 2 shows apartial section through an assembly of inj ection pumps, taken along theline 22 of Fig. 1.

It will, of course, be understood that the drawings and the followingdescription relate only to a singlepreferred executional em-' bodimentof the present invention, and that substantial alterations in .theconstruction and arrangement of the parts may be made without departingfrom the spirit and full scope of the invention.

' Referring by numerals to the drawings, the

injection pump body 1 may contain any number of pumps, the number ofwhich will depend upon the number of engine power cylinders. The pumpbarrel 2 may be formed integrally with the pump body, or may be maderemovable, in which case, a nut 3 is provided to hold the removablebarrel in position. Operativelyassociated with the pump barrel 2, is apump plunger 4 which may be formed with a cup-shape extension 5 for apurpose that will hereinafter appear. Positioned between the back of theextension 5 and the nut 3, is a plunger spring 6 serving to urge plunger4 to.its lower position. A plunger stop 7 may be threaded in a portionof the cylinder, and may be arranged to provide a certain amount ofadjustability for the stroke of plunger 4, by means of the insertion orremoval of shims 8 which will raise or lower the stop 7 sufliciently tolimit the downward travel of the plunger, which provision may result ina clearance between the plunger 4 and a crosshead 9. One end of thecrosshead is adapted to be positioned by a guide 10, formed in the nut 7while the opposite end 11 of the crosshead 9 is slidably guided in abarrel 12 formed as part of a casing 13.

The inner wall of the crosshead forms a socket 14, in which resides aball end 15 of the )ushrod 16, and permits the opposite end 17 of therod to move freely along an arcuate path, for purposes of adjustment ofthe pump stroke, as will appear hereinafter. An eccentric strap 18 ispivotally connected to the pushrod 16, by means of a pin 1 or theequivalent, and is rotatably mounted on a governor controlled eccentric20, preferably of tubular form, which is eccentrically mounted on thegovernor shaft 21, as a fixed center. It will be readily seen that theeccentric 20 has an incomplete rotational movement in either direction,which is transmitted through the strap and related parts, to the ableform (not shown), connected in automatic adjusting relation to the shaft21.

The end 17 of the pushrod 16 is adapted to be freely and adjustablymoved along an arc corresponding to the arcuate shape of upper surface22, on the rocker arm 23. This surface is preferably in the form of apart cylinupon the length of the der having a radius correspondingsubstantially to the length of the pushrod 16. The rocker arm 23 ispivotally mounted on a fixed pin 24. As will be seen from Fig. 1, thesurface 22 extends across and on each side of the pivot 24, for reasonswhich will later appear. The rocker is, by preference, provided with atappet roller 25, mounted on a pin 26 in a bifurcated portion of therocker arm 23. The roller is kept in contact with an injection cam .27,mounted on the cam shaft 28, which is driven in timed relation with thecrank shaft, (not shown), of the engine. The high point or nose 29 ofthe cam 27 is adapted to give the roller 25 and'its related rocker arm23, the required reciprocating movement to operate the injection pumpplunger.

Referring again to the pump body 1, the oil supply reservoir isconnected to the pump body by the passage 30. The pump chamber,

shown at 31, is provided with a spring loaded suction valve 32, locatedin communication with the supply passage 30. A spring loaded ischargevalve'33, controls an outlet passage for the fuel, into the dischargeline 34 leading to the injector.

It will be understood that the cam shaft 28 rotates in timed relationwith the crank shaft of the engine,'and may serve to actuate one or anynumber of the cams 27, corresponding to the number of power cylinders inthe engine.

As the nose of the cam 27 passes under the roller 25, the rocker arm 23is partially rotated about its fixed pivot 24, transmitting areciprocating movement to the pushrod 16, and hence to the pump plunger4. As the high point 29 passes beyond the roller, the pump plunger 4 isurged downwardly in the barrel 2, by spring 6, thus causing a suction inthe pump chamber 31. At this time the suction valve 32 opens, and fuelis drawn into the pump chamber. As the high point 29 of the cam 27 againcomes into contact with the roller 25, the rocker 23 is raised andimpels upwardly the pushrod 16 and the plunger 4, the displacement ofwhich results in a pres sure in the pump chamber 31, closing the suctionvalve 32 and opening the discharge valve 33, through which the fuel isdriven under pressure into the injector.

It will readily be seen that the amount of fuel injected into thecylinder depends pump stroke, and further, that the amount of fuelrequired depends on load conditions. As long as the load remainsconstant, the governor maintains a fixed contact position of the end 17of the pushrod with respect to the surface 22 of the rocker arm 23. Asthe load increases, the governor rotates the shaft 21 in ananti-clockwise direction, (as seen in Fig. 1), which moves the lower endof the pushrod to the right, thereby increasing the stroke of the pumpand the amount of fuel displaced and injected, in accordance with theload. As the load becomes less, the governor is arranged to rotate theshaft 21 in a clockwise direction (Fig. 1), which, through the eccentricand strap 18, moves the lower end 17 of the pushrod to the left, therebyshortening the stroke of the pump and decreasing the. amount of fuelinjected into the cylinder. By moving the lower end of the pushrod farenough to the left, the stroke of the pump may be reduced to zero, andall the fuel cut off, so as to stop the engine.

One feature of the invention is'found in a provision for minimizing thedragor frictional resistance that the governor must otherwise overcomein moving the end 17 of the pushrod over the surface 22 of the rocker23. The member 7 may, by means of shims 8, be raised sufliciently toserve as a stop,

acting against the lower face of the plunger to limit its downwardtravel, thus providing a slight clearance between the lower end 17 ofthe pushrod and the rocker 23 when the roller 22 is following the lowportions of cam 27. This clearance removes the spring pressure fromthese parts, and reduces the friction which must otherwise be overcomein moving the push rod across the face of the rocker when the governoris changing the stroke of the pump.

The assembly described will be seen to provide a compact, rugged meansof controlling fuel injection, in fulfillment of each of the objects ofthe invention as set forth above. Besides the advantages and economiesafforded by this invention. when used with a suitable governor, thedescribed device shows a quick and positive response to speedfluctuations and provides for a remarkably close speed regulation overthe entire range of engine speeds.

I claim as my invention:

1. In an assembly including an. injection pump and a pushrod actuatedmechanism therefor. an actuating cam, a pump plunger arranged to beactuated in one direction responsively to rotation ofsaid cam, a springarranged to actuate the plunger in the opposite direction. a rockeroperated by the cam. a pushrod mounted for swinging movement withrespect to said rocker, and operatively associating said pump plungerand cam. a crosshead pivotally engaging the pushrod. and a threaded stopfor said plunger. forming a guiding] member for said crosshead, saidrocker having a fixed pivot and an arcuate pushrod seat extending acrossand on each side of said pivot.

2. In an injection pump operating mechamsm, a cam, a cam'actuatedrocker, having a curved pushrod seat extending across its axis, a springpressed plunger arranged to be actuated by said mechanism, a pushrodoperatively associating said plunger and a construction in accordancewith rocker, a crosshead having a socket for receiving one end of thepushrod, and an extension engaging said plunger, an eccentric adapted tobe'rotated for adjusting the angular relation between the pathsof-travel of said plunger and pushrod, and an adjustable stop for theplunger, constituting a guide for the crosshead extension, and adaptedto relieve spring resistance against rotational movement of saideccentric.

3. In an injection pump assembly for an internal combustion engine, apump operating cam adapted to be rotated in timed relation with theengine, a tappet adapted to operate on said cam and having a fixedpivot,

' and a concave rod-receiving surface extending on each side of saidpivot, a push-rod adapted to be reciprocated under the influence of saidcam and said tappet, a pump barrel, a spring-pressed plunger operativelydisposed therein; a crosshead distinct from the pump plunger, serving asan operative connection between said pushrod and said plunger. saidpushrod being disposed in swingable relation to said crosshead andhaving a ball and socket connection therewith, a guide for saidcrosshead, including two threadedlv connected portions, one of saidportions arranged for rotation relative to the other portion toconstitute an adjustable stop for the spring-urged movement of theplunger whereby to permit free swinging movement of said pushrod, andmeans for varying the angular relation between said pushrod and saidplunger; said means comprising an eccentric. an eccentric shaft, and aneccentric strap pivotally connected to said pushrod, said last namedmeans being adapted upon said variation of angular relation to controland terminatedelivery of fuel by said pump by effecting variation in thestroke of said plunger.

EDWARD TuADAMS.

